William r



(No Model.)

W. R. PATTERSON.

THBRMOMBTRIG INDICATOR.

No. 402,347. Patented Apr. 30, 1889l m .u l l t m ww /i1 /(IIII a 1111 mVMYIIHWWH 0 n il 9, mlmlww,

1w #n NIH m 2 5. i! l 1 UNITED STATES PATENT OFFICE.

VILLIAM R. PATTERSON, OE CHICAGO, ILLINOIS, ASSIGNOR TO THE lVESTERNELECTRIC COMPANY, OE SAME PLACE.

TH ERMOMETRIC INDICATOR.

SPECIFICATION forming part of Letters Patent No. 402,347, dated April30, 1889.

Application filed October l, 1888. Serial No. 286,835. (No model.)

T0 @ZZ whom it may con/cern,.-

Be it known that LWILLIAM R. PATTERSON, a citizen of: the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Electric TemperatureRegulators, (Gase 58,) of which the following is a full, clear, concise,and exact description, reference being had to the accompanying drawings,forming a part of this specification.

My invention relates to apparatus for automatically indicating changesin temperature. By its use one is enabled to keep the temperature of aroom or building within certain limits.

My apparatus is so arranged that when the temperature rises above acertain point an electrical signal will be given, and in like mannerwhen the temperature falls below a certain point the fact will beelectrically indicated.

illy invention consists of a thermostat in which mercury is moved by theexpansion and contraction of oil or other non-conducting liquid,preferably paraine-oil.

My invention also consists inthe combination of parts hereinafterdescribed and claimed.

My invention is illustrated in the accompanying drawings, in which-Figure l is a sectional view of a thermostat embodying my invention.Fig. 2 is a side view of the same. Fig. 3 is a modified form of thethermostat. Fin". i is a view, partially in section, of a .ackand-piniondevice forregulating the wires in the thermostat.

Referring new to Fig. l, the oil a is contained in the closed vessel h,the space containing the oil being annular, as shown, so that a largesurface maybe exposed. The vessel should be ot metal or other goodconductor of heat. The bent tube c is connected with the reservoircontaining the oil, as shown. This tube is prefer( bly of glass, and isconveniently placed within the opening in the vessel containing the oil,as shown. The end of the tube not connected with the oil-chamber may beleft open, if desired. Enough mercury should be placed in the tube toinsure its presence in both branches while the oil is at a temperaturebetween the desired limits. I find it best in practice to place enoughmercury in the tube to extend into both branches at any temperature towhich the apparatus may be subjected. One pole of the battery d isconnected permanently with the mercury by wire f. The wires g g arebranched from the other pole of the battery through suitable signalingapparatus or annunciators, g lo', and so arranged that when thetemperature falls below the desired limit one of the circuits will beclosed. The other branch is so connected that when the temperature risesabove the desired limit the mercury will come in contact with said otherbranch, thus closing the circuit of the battery through the othersignaling-instrument. As long as the temperature does not fall below orrise above these maximum and minimum points the circuit of the batterywill remain open. Thus in Eig. l it will be seen that the mercury is incontact with wire g at h. lf now the temperature should be increased,the oil a will eX- pand, thus forcing the mercury d down from the point7L and up toward point t' until on reaching point t' contact will bemade between the mercury and wire k at said point '27. As long as themercury remains between the points 7L and t' it is evident that bothbranches of the circuit will remain open. The wires g and 7c areinsulated, except at the ends h and fz', as indicated.

After determining within what limits the temperature is to be regulated,the position of the naked contacts 7L and /L' ot the wires with respectto the mercury and each other may be accordingly regulated in anysuitable manner, the oil being heated. or cooled artificially, asrequired.

The diiterentbranches of the wires g 7c may, if desired, be connectedwith the racks Z m, as shown in Fig. i. By turning the pinions Z m theposition of the wires may be changed, so as to bring the bare portion atthe points required.

The tubes I? m2, holding the racks and pinions, are preferably of hardrubber, and serve as guides 'tor the racks. Connection with the batterymay be made through the spindles 0 p, which carry the pinions,respectively.

In Fig. 3 I have shown amodiication of my apparatus. Instead of havingthe end of the tube containing the mercury open, I provide a closedchamber, q, containing air, at one end of the tube containing themercury. The oil is placed in the closed reservoir r at the opposite endof the tube. The expansion of the oil by heating forces the mercurytoward the air-reservoir, the air being compressed. I preferably IniXmetallic filings with the oil, in order that the oil may be moresensitive to changes of temperature, especially when the reservoircontaining the oil has only a small surface exposed.

The circuits shown in Fig. 3 and the operation of the device are thesame as heretofore described. The branch wires I preferably run throughstuffing-boxes r q', in order that they may be adjusted without openingthe oilchamber or airchamber.

Having thus described myinvention, I claim as new and desire to secureby Letters Patentl. The combination, with the mercury, of anon-conducting liquid placed in the bent tube containing said mercuryand electrical connections-one on each side of said mercurywith whichthe mercury is adapted to make electrical connections alternately as theteinperature rises and falls, substantially as and for the purposespecilied.

2. The combination, with atube containing' mercur of closed chamberswoneat each end of the said tube-one of said chambers containing aninsulating-liquid and the other containing air, and an electric circuitpermanently connected with said mercury and extending' through a batteryto twosignal-instruments and from said signalinstruments in two 4obranches to points 7L and z' on opposite sides of the mercury, wherebythe circuit is closed through one signal-instrument or the other as theoil expands or contracts to move the mercury into contact with one orthe other of said points.

3. The combination, with the mercury, of oil contained in the same tubetherewith and branch electric circuits and contact-points on differentsides of the said mercury in said 5o tube, whereby one circuit or theother will be closed asv the temperature rises or falls below the pointto which the apparatus is adjusted.

4. The combination, with the annular reservoir b, containing aninsulating-liquid, a, of the bent tube c, containing mercury, placedwithin the opening in the reservoir, said mercury being in both branchesof said tube, said tube being closed at one end of the reservoir b, andthe other end of said tube, above the 6o mercury, containing air, thebattery d, one pole of which is connected permanently with the mercury,while the other pole is extended by the branches g 7c to points 7L andi, to which points the mercury is adapted to be alternately forced bychanges in the temperature of the oil, and the signal-instruments kg-one in each of said branches-whereby changes of temperature withincertain limits will. be indicated by the signal-instruments, substan- 7otiallyas and for the purpose specified.

In witness whereof I hereunto subscribe my name this 28th day ofSeptember, A. D. 1888.

WILLIAM R. PATTERSON.

Witnessesf GEORGE P. BARTON, ELLA EDLER.

